According to Davidson College Professors of Psychology Mark Smith and Scott Tonidandel, the number one predictor of whether kids use drugs is whether their friends use drugs. The departmental colleagues have recently received a $1.38 million five-year grant from the National Institute on Drug Abuse to explore the psychology behind the trend.

Their project, titled "Social Influences on Drug-Seeking Behavior," will study two known factors that play a role in the social influences of drug abuse-"selection" and "social learning."

"Selection" suggests that friends of drug users are often drug users themselves because users choose peers who already share their same attitudes, beliefs and behaviors. "Social learning" implies that friends share similar behaviors because they learn behaviors from one another.

Smith noted that selection and social learning are not mutually exclusive. "We know they both contribute to drug abuse, but we don't know to what degree each contributes," he said. "That's what we are trying to figure out."The project will involve experiments by Smith in cocaine consumption by rats, and analysis of the experimental results by Tonidandel.

Smith has observed that when two rats who are allowed to self-administer cocaine are placed side-by-side, they both choose to consume a significant amount of cocaine. However, when a self-administering rat is paired with a rat who does not have access to cocaine, the rat who has access will not readily begin self-administering.

"This is the first time I've encountered rats who resist self-administration," said Smith. "Normally, when I give rats access to cocaine, either in isolation or with a buddy who also has access, the rats self-administer the drug continuously until the session ends."

Smith and Tonidandel believe these findings suggest that animals are significantly influenced by what their peers are doing. Additionally, since the rats do not choose who they're paired up with, the factor of "selection" does not play a role in this initial series of experiments.

The two scientists hope to use the funding to answer several questions. Will two rats who self-administer copiously when together diminish their consumption when in isolation? Will a rat who lives with an abstaining buddy, and takes little to no drugs, begin self-administration if alone?

Smith takes gender into account in his experiments, and also considers the different stages of drug abuse-acquisition, escalation, recovery and relapse.

This grant is the second of $1 million dollar magnitude Smith has received in the past three years. He employed his first grant to explore the effectiveness of exercise as an intervention in drug addiction. He said, "We found that exercise is remarkably effective in helping rats reduce drug abuse behaviors in all stages of the addictive process. But it's important to investigate other interventions such as social influences because drug abuse is a complex phenomenon."

The new study will be among the first to look at social influences of drug self-administration with rats in a social setting because it is difficult for multiple rats to interact without interference of traditional self-administration gear they must wear. However, Smith has enabled rat interaction by creating cages with a minimal barrier between two animals, allowing for visual, audio, olfactory, and limited tactile contact with one another.

The new grant will fund a full-time Ph.D.-level scientist and an additional lab technician to help with the project. Student lab assistants Geoff Pietz '12, Maryam Witte '12, and Justin Strickland '14 and lab technician Liz Pitts '11 will also be involved. The grant will also pay for rats, cages, and animal maintenance.

Smith, a 1992 graduate of Lenoir-Rhyne University, has taught classes in general psychology, learning, behavioral pharmacology and clinical psychopharmacology at Davidson since 1998.

In graduate school at UNC Chapel Hill, he studied the pain-relieving properties of opioid analgesics such as heroin, morphine and Oxycontin. During a sabbatical at Wake Forest University seven years ago he began animal studies with self-administration of cocaine.

He began by looking for a drug that would help people overcome cocaine addiction. But his studies have led him to question that an anti-cocaine pill will ever be discovered. He noted, "For heroin there's methadone, for nicotine there's Chantix, and for alcohol there's naltrexone. But I think people will need some form of behavioral intervention for continued improvement with cocaine addiction."

Smith recognizes that addiction is a chronic disease, with about half of all users relapsing within a year after treatment. He said, "There are a multitude of both genetic and environmental determinants in drug abuse. As a consequence, you're going to need a large arsenal of interventions to combat the disorder.